Window coverings may utilize a loop cord drive to permit a user to actuate the raising or lowering of the window covering. The looped cord of a loop cord drive often includes beads or stops on the looped cord of the loop cord drive. The cord of the looped cord may be a cord formed from intertwined elongated members, or may be a polymeric elongated member or may be defined by a chain. Typically, the elongated members of the looped cord is flexible. The looped cord typically has stops attached thereto. The stops may be beads or other types of stops connected to the looped cord. Examples of loop cord drive systems, which may also be referred to as endless cord drive systems, may be appreciated from U.S. Pat. Nos. 6,749,000, 6,536,503, and 5,465,779.
Typically, looped cords include a top end that is entrained along a drive mechanism of the loop cord drive and a bottom end that hangs freely and is positioned adjacent to window covering material of the window covering. A user may rotate the looped cord in one direction to raise the window covering and rotate the looped cord in an opposite direction to lower the window covering. The looped cord often extends from adjacent to a headrail to a relatively low position to permit users to easily grab or manipulate the looped cord. Such a size, however, also permits small children to occasionally play with the looped cord or to come in contact with the looped cord.
In some instances, a relatively long looped cord may pose a threat to an unsupervised child. Small children such as toddlers or babies may play with the cord or may become entangled within the looped cord. For instance, a low freely hanging looped cord may be accidentally positioned near a toy box or dresser on which an unsupervised child may climb. Child entanglement with a looped cord may be dangerous and can pose a strangulation risk to the child.
For several years, the art has offered tie downs for looped cords. These tie downs consist of a pulley around which the cord passes and which can be attached to a window frame. The pulley does not prevent the loop cord from moving such that the loop cord can always be used to raise or lower the blind. This type of tie down is sometimes called a cord tension device.
A second type of tie down is a hook around which the cord is tied. When the cord is secured to the hook, the cord cannot be used to lower or raise the blind.
There is a need for a tie down or cord tension device that has the properties of both the pulley type and the hook type known in the art. Such a tie down would enable the cord to move when in an unlocked position and prevent cord movement when in a locked position. Preferably, the tie down could be installed so that the cord is always locked, always unlocked, or capable of being locked or unlocked by the user.